US ties with Europe

Trump election: Juncker warns president may upset US ties with Europe

"We will need to teach the president-elect what Europe is and how it works," Mr Juncker told students in Luxembourg.

The Commission chief predicted that two years would be wasted while Mr Trump "tours a world he doesn't know".

His remarks contrasted with other EU leaders' more muted reaction to the Tuesday's shock election result.

American cities have seen angry protests since Mr Trump's election victory over the Democratic candidate, Hillary Clinton.